<?php

namespace app\home\logic;

use think\Model;

class Unique extends Model {

    private static function _getMapbit($width) {
        $mapBits = array(
                4 => array(
                        10, 2, 11, 3, 0, 1, 9, 7, 12, 6, 4, 8, 5,
                ),
                5 => array(
                        4, 3, 13, 15, 7, 8, 6, 2, 1, 10, 5, 12, 0, 11, 14, 9,
                ),
                6 => array(
                        2, 7, 10, 9, 16, 3, 6, 8, 0, 4, 1, 12, 11, 13, 18, 5, 15, 17, 14,
                ),
                7 => array(
                        18, 0, 2, 22, 8, 3, 1, 14, 17, 12, 4, 19, 11, 9, 13, 5, 6, 15, 10, 16, 20, 7, 21,
                ),
                8 => array(
                        11, 8, 4, 0, 16, 14, 22, 7, 3, 5, 13, 18, 24, 25, 23, 10, 1, 12, 6, 21, 17, 2, 15, 9, 19, 20,
                ),
                9 => array(
                        24, 23, 27, 3, 9, 16, 25, 13, 28, 12, 0, 4, 10, 18, 11, 2, 17, 1, 21, 26, 5, 15, 7, 20, 22, 14, 19, 6, 8,
                ),
                10 => array(
                        32, 3, 1, 28, 21, 18, 30, 7, 12, 22, 20, 13, 16, 15, 6, 17, 9, 25, 11, 8, 4, 27, 14, 31, 5, 23, 24, 29, 0, 10, 19, 26, 2,
                ),
                11 => array(
                        9, 13, 2, 29, 11, 32, 14, 33, 24, 8, 27, 4, 22, 20, 5, 0, 21, 25, 17, 28, 34, 6, 23, 26, 30, 3, 7, 19, 16, 15, 12, 31, 1, 35, 10, 18,
                ),
                12 => array(
                        31, 4, 16, 33, 35, 29, 17, 37, 12, 28, 32, 22, 7, 10, 14, 26, 0, 9, 8, 3, 20, 2, 13, 5, 36, 27, 23, 15, 19, 34, 38, 11, 24, 25, 30, 21, 18, 6, 1,
                ),
        );
        return $mapBits[intval($width)];
    }

    /**
     * @return string
     */
    public static function generateNumber($id, $prefix = 10, $width = 8) {
        return sprintf("%s%s", $prefix, self::encode($id, $width));
    }

    /**
     *
     * @param integer $id id
     *
     * @return integer
     */
    public static function encode($id, $width) {
        $maximum = intval(str_repeat(9, $width));
        $superscript = intval(log($maximum) / log(2));

        $r = 0;
        $sign = 0x1 << $superscript;
        $id |= $sign;
        $mapbit = self::_getMapbit($width);
        for ($x = 0; $x < $superscript; $x++) {
            $v = ($id >> $x) & 0x1;
            $r |= ($v << $mapbit[$x]);
        }
        $r += $maximum - pow(2, $superscript) + 1;
        return sprintf("%0${width}s", $r);
    }

    /**
     *
     * @param integer $id id, mostly database primary key
     * @param integer $ts timestamp
     *
     * @return string
     */
    public static function get($id, $width, $ts = null) {
        return sprintf('%s', self::encode($id, $width));
    }
}